1. The "Can'ts" that a society must ponder, and weigh carefully, always:
You can't legislate against stupidity. You can't force people to mingle. You can't help someone who doesn't want, and/or isn't ready to be helped.
2. The "Musts" that a society must ponder, and weigh carefully, always:
You must provide equity of return for participation in keeping things going in a community, doing it via majority rule through the Democratic expression of a truly informed electorate.
Both the community as a whole, and the individual, must live by the rule of law, formed by the consensus of each community, representing themselves as participating citizens.
You must find a way to embrace, and facilitate, the ongoing difficulty of balancing the needs of the individual with the needs of the community as a whole, no matter how hard that gets.
You must find a way to tolerate (mitigating the harm of bad choice behavior as humanely as possible), and care for the disaffected (even if it's just minimal food, shelter, and basic health care).
You must demarcate between criminal, and sick, with considered deliberation, recognizing the difficult tension between minimizing harm to the community, and seeking to help those who see they are sick, and are ready to be helped.
You must change how you conceive of incarceration so that it is no longer meant as punishment. Incarceration must be seen as a community's loss of trust in an individual, and the period of time involved seen as what it will take for the community to gain that trust back. And we must do this because society as a whole must never allow itself to think that it has the right to punish its individual citizens. And in this the right of the individual harmed to seek justice must end at the point of stopping the perpetrator from causing further harm. Society as a whole must do this because punishment, and vengeance, become too difficult to separate in the understandable emotions of the harmed. And once a society embraces vengeance as a way of life, terrible extremes of action become far too possible.
There are probably more things you could add to these two lists. I'd be curious to see what you guys think on that score.